Michigan State UniversityMichigan State UniversityCloseMenu buttonMenu and Search buttonOpenCloseNewsVideoEventsresourcesnewsletterExpertsProgramsYouTubeFacebookTwitterGoogle PlusAsk an ExpertSee how spartans make a difference in Michigan. MI Spartan Impact

The 2014 summer will be remembered as cool across northern Michigan, with late dry bean planting caused by a wet June.

Dry bean root rots are usually caused by Rhizoctonia, Fusarium and Pythium pathogens. These organisms can survive for years in infested soil. When the right conditions are present, disease develops. In 2014, heavy rains were experienced in some dry bean growing regions in Michigan, with serious root rot problems following. Then, cool and dry conditions slowed crop development, adding to the problem. Conditions that favor root rot development include high soil moisture, soil compaction, poor drainage and frequent bean crops.

Above-ground symptoms of root rot on dry beans may include:

Seedling death (damping off).

Stunted growth.

Yellowing of lower leaves.

Early leaf drop.

Brownish streaks in vascular tissue up to first node.

Below-ground symptoms may include:

Sunken, reddish-brown lesions on roots or hypocotyl.

Death of primary root, sometimes secondary root.

Development of lateral roots above infection site.

If root rot is suspected, dig up a few yellowed plants and inspect the roots carefully. This will be the most dependable in-field diagnostic tool.

Yield losses depend on disease severity, which is affected by environmental conditions from planting through flowering. Bean plants can recover from root rot if conditions improve and soil moisture remains adequate for the reduced root system to access needed moisture and nutrients. Losses can range from slight to 100 percent.

August 1, 2016 | Christina DiFonzo | We’ve got perfect spider mite conditions due to this summer’s dry weather and the arrival of August. Irrigation can complicate decisions. Here are tips to get any sprays right.